Q355B steel plate is a low-alloy, high-strength structural carbon steel that is extensively employed in the fields of prefabricated construction, high-rise structures, and industrial plants, while adhering to the GB/T 1591-2018 standard.
Distinguished by its superior weldability, high tensile strength, and excellent durability, this steel grade serves as an ideal material for fabricating columns, trusses, and beams, making it suitable for a wide range of load-bearing structures and commercial building applications.
What Is High-Strength Q355B Steel Plate?
High-strength Q355B steel plate is a low-alloy, high-strength structural steel plate defined by the Chinese standard GB/T 1591-2018; this steel grade features a minimum yield strength of 355 MPa and excellent weldability. As a versatile material, Q355B is widely utilized in construction, heavy machinery, bridge building, and shipbuilding, and is frequently regarded as a modern, high-performance upgrade and substitute for Q235 and Q345 steels.
Chemical Composition of Q355B steel plate
| Material | C | Si | Mn | P | S | Cr. | Ni | Cu | N |
| Q355B | ≤0.20% | ≤0.55% | ≤1.60% | ≤0.030% | ≤0.030% | ≤0.30% | ≤0.30% | ≤0.40% | ≤0.012% |
Mechanical Properties of Q355B steel plate
| Property | Typical Value/Range (Metric) |
|---|---|
| Yield Strength (0.2% offset) | 355 MPa (Min) |
| Tensile Strength | 470 - 630 MPa |
| Elongation | ≥ 20% |
| Impact Strength (Charpy) | ≥ 27 J |
| Impact Test Temp | +20°C |
Why Choose Q355B Steel Plate for Prefabricated Steel Buildings?
High Strength and Load-Bearing Capacity:Q355B possesses a high yield strength (typically 355 MPa)-approximately 40% higher than that of ordinary low-carbon steel. The use of Q355B allows for a reduction in the cross-sectional dimensions of structural components; this not only reduces the building's dead load but also increases usable interior space.
Seismic Resistance and Low-Temperature Toughness:Q355B exhibits excellent toughness (the "B" grade designation indicates impact toughness at 20°C), enabling it to absorb energy during natural disasters such as earthquakes and thereby ensure structural safety. Furthermore, this steel retains stable mechanical properties in low-temperature environments, making it suitable for construction projects across diverse geographical regions.
Excellent Weldability and Processing Performance:As a low-alloy structural steel, Q355B combines high strength with excellent weldability. This attribute is critical for the factory-based welding and on-site installation processes involved in prefabricated construction, ensuring the robustness and structural integrity of connections between components.
Enhanced Construction Efficiency:As a key material in prefabricated and modular construction, Q355B undergoes cutting, welding, and rust removal within the factory environment, leaving only hoisting and bolted connections to be performed on-site. This approach not only shortens the overall construction cycle but also reduces on-site labor intensity and minimizes environmental pollution.
Applications of Q355B Steel Plate for Prefabricated Steel Buildings
Load-Bearing Structural Components: Q355B serves as the primary material for constructing the main structural frameworks of high-rise buildings and large-scale steel industrial plants; it is utilized to fabricate critical load-bearing elements such as beams and columns.
Prefabricated Composite Walls: In modular construction projects-including schools, hospitals, apartment complexes, and multi-story public buildings-Q355B is frequently employed to fabricate "truss-stiffened, multi-cavity composite steel shear walls."
Portal Frame Structures: In prefabricated steel structures such as industrial warehouses and workshops, Q355B steel plates are often processed into H-beams to serve as the primary load-bearing framework, working in conjunction with C- and Z-section steel members (purlins) to facilitate rapid assembly.
Specialized Structures and Exterior Walls: Beyond the main structural framework, Q355B steel plates are also utilized in the construction of building roofs, floor slabs, and exterior wall sections, making them well-suited for applications requiring high structural reliability.
S355JR vs. Q355B Steel Plate：How To Choose?
Both Q355B and S355JR are low-alloy, high-strength structural steels possessing similar mechanical properties. Specifically, Q355B (Chinese Standard GB/T 1591) is an ideal choice for projects located in China or Asia, whereas S355JR (European Standard EN 10025-2) is the preferred choice for European projects. In general construction applications, these two steel grades can be used interchangeably, provided that the impact toughness requirements (achieving 27 J at +20°C) are met.
How To Choose?
Project Location and Standards:
If the project complies with Chinese standards (GB/T 1591), it is recommended to select Q355B steel.
If the project is located in Europe or adheres to European standards (EN 10025-2), S355JR steel should be selected.
Impact Toughness Requirements:
Both of the aforementioned grades are required to undergo impact testing at a temperature of +20°C, with a minimum impact energy requirement of ≥ 27 J.
If the project imposes stricter requirements regarding low-temperature impact toughness (necessitating testing at 0°C or -20°C), grades Q355C/D or S355J0/J2 should be specified instead of Q355B/S355JR.
Welding and Processing:
Q355B steel exhibits excellent weldability, with welding performance comparable to that of S355JR.
For the fabrication of critical components, S355JR+N (Normalized) steel is sometimes given preference to ensure a higher degree of uniformity in the material's microstructure.
Supply and Cost:
In the Asian market, Q355B steel is typically available at a lower price point.
Conversely, in the European market, S355JR steel is generally available in ample stock from local suppliers.
If you require further details regarding Q355B steel plates, please do not hesitate to contact us.
As a leading manufacturer of Q355B steel plates in China, GNEE boasts 20 years of extensive industry experience. Our warehouses maintain a standing inventory of over 50,000 tons year-round, ensuring that orders can be shipped in as little as seven days. In terms of quality assurance, we are a dual-certified supplier-holding both API and ISO certifications-and we welcome inspections by third-party agencies such as SGS, BV, and Lloyd's.
By choosing our Q355B steel plate products, you will benefit from our comprehensive, customer-centric support services, as well as our extensive value-added processing capabilities. We would be delighted to provide full-spectrum support and assistance for your project.
Contact now to get Q355B steel plate
| Type | Q355B |
| Standard | AISI, ASTM, BS, GB, DIN, JIS, etc |
| Certificate | ISO,SGS,CE |
| Length |
Production according to customer requirements |
| Thickness | 8-160MM |
| Width | 2000-2500MM |
| Surface | Coated |
| Technique | Hot rolled |
| Package | Available on request or Standard Export Packing |
| Application | Widely used in Building Construction, Bridge, Architecture, Vehicles Components,hipping,High pressure container, Boiler, Large Structure steel etc. |
What is the ASTM equivalent of Q355B steel?
The equivalent ASTM material for Q355B steel is ASTM A572 Grade 50. ASTM A572 Grade 50 is a structural steel with high strength and low alloy content that is widely utilized in structural applications.
What is Chinese steel grade Q355B?
Q355B steel plate is a low-alloy high-strength steel plate. Q355B steel plate has excellent mechanical function, low temperature function, and excellent plasticity and weldability. Q355B steel is used to make medium and low pressure container, oil tank, vehicle, crane, mining machinery, power station, bridge, etc.
What is the impact test for Q355B?
Q355B square steel pipe exhibits excellent impact performance. At a room temperature of 20°C, its impact absorbed energy is no less than 34J. This value reflects the material's ability to absorb energy when subjected to impact loads and is a key indicator for evaluating its resistance to brittle fracture.